Leads Biolabs Announces Completion of Patient Enrollment in Pivotal Trial of Opamtistomig Monotherapy for Extrapulmonary Neuroendocrine Carcinoma

USA - English

• APAC - Traditional Chinese
• APAC - English

NANJING, China, Aug. 14, 2025 /PRNewswire/ -- Nanjing Leads Biolabs Co., Ltd. ("Leads Biolabs" or the "Company," Stock Code: 9887.HK) today announced the successful completion of patient enrollment in the ongoing single-arm, pivotal registrational clinical trial (CTR20213023) for Opamtistomig (LBL-024), a novel PD-L1/4-1BB bispecific antibody.

This marks the world's first registrational clinical trial evaluating an immunotherapy monotherapy for extrapulmonary neuroendocrine carcinoma (EP-NEC). The study, led by Professor Shen Lin from Peking University Cancer Hospital and conducted across multiple medical centers, aims to evaluate the efficacy and safety of Opamtistomig in patients with advanced EP-NEC who failed at least two lines of chemotherapy.

EP-NEC is a highly aggressive, immunologically "cold" tumor. The current first-line standard treatment for advanced EP-NEC remains platinum-based chemotherapy, with an objective response rate (ORR) of 30%-50% and a median overall survival (mOS) of approximately 1 year. For patients with platinum-resistant, no established second-line standard of care exists, representing a pressing unmet need for new therapeutic options.

Dr. Charles Cai, Chief Medical Officer of Leads Biolabs, stated:" As the first PD-L1/4-1BB-targeted bispecific antibody globally to have reached pivotal single-arm registrational stage, Opamtistomig has demonstrated compelling antitumor activity and favorable safety in early trials. Completing enrollment months ahead of schedule accelerates clinical development timelines and reflects both strong confidence of investigators in the trial design and the urgent patient need for effective, safer therapies. We remain committed to advancing rigorous clinical development across multiple indications, including EP-NEC."

Dr. Xiaoqiang Kang, Founder, Chairman and CEO of Leads Biolabs, added, "This achievement was made possible by the exceptional execution of our clinical team, the dedication of investigators, and the trust of patients and their families. Every data point in this study represents hope for patients facing a devastating disease. Guided by our mission-care for life, focus on innovation, and win win cooperation-we will continue to invest in R&D to accelerate Opamtistomig's global development and deliver transformative therapies worldwide."

About Opamtistomig

Opamtistomig (LBL-024) is a potential first-in-class bispecific antibody simultaneously targeting PD-L1 and the co-stimulatory receptor 4-1BB. It is the first 4-1BB-targeting bispecific antibody globally to reach the single arm pivotal trial stage as a monotherapy and holds promise to become the first approved treatment specifically for extrapulmonary neuroendocrine carcinoma (EP-NEC), a malignancy with significant unmet medical need.

Developed using Leads Biolabs' proprietary X-Body™ bispecific platform, Opamtistomig features a 2:2 format with two binding domains each for PD-L1 and 4-1BB, and an optimized affinity ratio. This design allows Opamtistomig to both reverse PD-L1–mediated immune suppression and selectively enhance T cell activation, resulting in potent, synergistic anti-tumor effects.

In Phase I/II clinical trials in China, Opamtistomig has demonstrated promising efficacy and a favorable safety profile in patients with advanced EP-NEC, both as monotherapy and in combination with chemotherapy. The lack of a standard of care in EP-NEC supports the pursuit of accelerated approval through a single-arm pivotal study.

In recognition of its clinical potential, Opamtistomig received Breakthrough Therapy Designation (BTD) from the National Medical Products Administration (NMPA) in China (October 2024), and Orphan Drug Designation (ODD) from the U.S. Food and Drug Administration (FDA) for neuroendocrine carcinoma (November 2024).

Notably, 4-1BB agonism can reactivate exhausted T cells and drive robust proliferation, making it particularly promising for PD-1/PD-L1-resistant or immunologically "cold" tumors. Beyond EP-NEC, Opamtistomig has been approved for clinical trial across multiple cancer types with high unmet need, including small cell lung cancer (SCLC), biliary tract cancer (BTC), ovarian cancer (OC), non-small cell lung cancer (NSCLC), esophageal squamous cell carcinoma (ESCC), hepatocellular carcinoma (HCC), gastric cancer (GC), triple-negative breast cancer (TNBC), and malignant melanoma. Encouraging clinical activity has already been observed in SCLC, BTC, OC, and other cancer types, supporting Opamtistomig's potential as a broad-spectrum oncology therapy.

About EP-NEC

Neuroendocrine carcinoma (NEC) is a class of poorly differentiated, high-grade neuroendocrine neoplasms (NENs), which originate in the diffuse neuroendocrine cell system and can occur in many different sites. NEC can be categorized into pulmonary NEC and EP-NEC. EP-NEC exhibits similar highly aggressive and metastatic characteristics to small cell lung cancer (SCLC). Most patients are diagnosed at a later stage or already have distant metastases, resulting in rapid disease progression and a poor prognosis.

Currently, the primary first-line treatment for advanced EP-NEC involves platinum-based chemotherapy, achieving an overall response rate (ORR) of approximately 30% to 50%, with a median overall survival (mOS) of only approximately one year. Treatment options for patients with platinum-resistant are limited, and there are no established second-line standard of care for patients who progress after first-line therapy. These underscore the urgency to develop novel therapeutic approaches.

About Leads Biolabs

Founded in 2012, Leads Biolabs is a clinical-stage biotechnology company dedicated to the discovery, development, and commercialization of innovative therapies to address underserved medical needs in oncology, autoimmune, and other severe diseases both in China and globally.

We are a front-runner in next-generation immuno-oncology treatments with a differentiated pipeline of 14 innovative drug candidates, including six clinical-stage drug candidates, of which four lead products are among the top-tier clinically advanced candidates globally.

We adopt a science-driven R&D approach and have successfully established comprehensive R&D capabilities spanning antibody discovery and engineering, in vivo and in vitro efficacy evaluation, as well as druggability assessment. We have also developed multiple proprietary technology platforms, including LeadsBody™ platform (a CD3 T-cell engager platform), X-body™ platform (a 4-1BB engager platform), which serve as the cornerstone for our continued innovation and have been validated by the clinical outcomes of our bispecific antibody portfolios.

We have established integrated capabilities across early discovery, translational medicine, clinical development, CMC and business development. The innovative nature and competitive strengths of our drug candidates, coupled with our global perspectives, proactive strategy, and efficient clinical validation, have made us an attractive partner for leading industry players and venture capitals. For more information, please visit https://en.leadsbiolabs.com/

SOURCE Leads Biolabs